Conventionally, a displacement-type marine vessel whose hull partly travels in water is known to sometimes have a fin called a stern tunnel fin for inducing flow to a position above a propeller, which is mounted to extend from a position on the hull in front of the propeller to a position on the hull above the propeller. In the displacement-type marine vessel as such, since the stern tunnel fin accelerates and makes uniform the flow into the propeller and prevents propeller cavitation, vibration of the hull is restrained (For example, see Patent Citation 1)
A stern shape is proposed which maintains a certain distance between a propeller and a hull by bending the bottom of the stern above the propeller upward. With this stern shape, the vibration of the stern due to a vibratory force of the propeller is maintained to be an equivalent to that of a vessel having the stern shape of the related art, so that improvement of propulsive efficiency is possible by increasing the diameter of the propeller (For example, see Patent Citation 2).
Among planing high-velocity ships which travel with their hull raised to a level higher than a draft line and in the velocity range in which the Froude number is larger than the last hump, a vessel type called chine is known. The chine vessel type has a vessel bottom portion formed into a dome shape, and the vessel bottom portion and the side plates of the vessel join at an angle. (For example, see Patent Citation 3)    Patent Citation 1: Japanese Examined Utility Model Application, Publication No. 59-28960 (see FIG. 5)    Patent Citation 2: The Publication of Japanese Patent No. 2716658 (see FIG. 1 and FIG. 2)    Patent Citation 3: Japanese Unexamined Patent Application, Publication No. 61-044090